1. Technical Field
The present invention relates to a composition for an antifreeze or a coolant, containing (a) cyclohexane dicarboxylic acid; (b) an azole- or thiazole-based inhibitor; and (c) a metal of group II, V, VI, or VII element.
2. Background Art
Generally, a composition for an antifreeze or a coolant contains, as a main material, ethylene glycol or propylene glycol. The composition contains, as main components, a carboxylic additive and an organic material in order to prevent corrosion of aluminum- and iron-based parts. Aliphatic polybasic acid type surfactants (Japanese Patent Publication No. 2002-38137), dicarboxylic or tricarboxylic acid having C10-C20 alkyl group (Japanese Patent Publication No. 2000-219981), flavone derivatives (Japanese Patent Publication No. 2001-98258), polymaleic acid, polyacrylic acid, or copolymers of their monomers (Japanese Patent Publication No. 2001-279235), lithium compounds (Japanese Patent Publication No. Hei 9-263976), and the like have been reported as anti-corrosive agents for the aluminum- and iron-based parts.
On the other hand, since only the combination of carboxylic and organic additives cannot have anti-corrosive durability at low concentrations of 30% or less, a phosphate or silicate additive (U.S. Pat. Nos. 4,873,011, 5,422,026, 4,598,205, 4,657,689, 4,647,392, and 5,064,552) is used as a supplement agent. However the phosphate and silicate additives have faults of a fast depletion rate and bad stability. The phosphate additive reacts with calcium or magnesium ions, which may be contained in the antifreeze or coolant dilution water, to form calcium phosphate and magnesium phosphate which are insoluble in water, thereby causing blockage and corrosion due to scale and hindering the long-term anti-corrosion for aluminum- and iron-based parts. Silicate may be easily gelled due to its poor stability, may generate abrasive SiO2 particles, resulting in a loss of anti-corrosive capability, thereby accelerating abrasion of mechanical seals of the water pump to cause a liquid to leak, or may block the core of the radiator by precipitation, causing an overheating phenomenon.
Throughout the entire specification, many patent documents are referenced and their citations are represented. The disclosures of cited patent documents are entirely incorporated by reference into the present specification, and the level of the technical field within which the present invention falls and details of the present invention are explained more clearly.